MAF problem- tracks w/o car running & sets code

[BM Computer Src]

I just finished putting my TTA back together after a blown head gasket and a surprise wiped cam. I had no MAF problems prior to this, and the car was down for about a month while I did the repairs. After idling for 10 seconds or so, its sets the code MAF LOW. The car will run but when trying to move it, anything past just slight throttle wont work. I recorded it on Directscan and here is what I found:

1. Key on, engine OFF: press throttle to floor and the MAF goes from reading 6 grams to 255! This is not possible; the engine is not running! The MAF numbers track perfectly with the TPS; like at 1/2 throttle, its 1/2 of 255. So odd!

2. When engine is running and throttle is pressed "slightly" the MAF jumps to the MAX and the LV8 follows, causing the car to buck and stumble.

So, is the MAF bad or what? I'll swap for another in the coming days, but this just seems odd! It did pass the "tap" test fine.

Thanks,
Bob

 

[BM Computer Src]

ttt

 

[Roc87]

What does Directscan say when you unplug the MAF, and do the same test?

 

[petesgn]

Maybe bad or loose ground at the rear of cylinder head ?

 

[bruce]

Originally posted by BM Computer Src
I just finished putting my TTA back together after a blown head gasket and a surprise wiped cam. I had no MAF problems prior to this, and the car was down for about a month while I did the repairs. After idling for 10 seconds or so, its sets the code MAF LOW. The car will run but when trying to move it, anything past just slight throttle wont work. I recorded it on Directscan and here is what I found:

1. Key on, engine OFF: press throttle to floor and the MAF goes from reading 6 grams to 255! This is not possible; the engine is not running! The MAF numbers track perfectly with the TPS; like at 1/2 throttle, its 1/2 of 255. So odd!

2. When engine is running and throttle is pressed "slightly" the MAF jumps to the MAX and the LV8 follows, causing the car to buck and stumble.

So, is the MAF bad or what? I'll swap for another in the coming days, but this just seems odd! It did pass the "tap" test fine.

Thanks,
Bob

The default for the MAF failing the self diagnostics, is that the system goes Alpha-N, and uses fixed gm/sec reading as a function of TPS.

Clear the codes, and repeat without starting the engine.

IAC and TPS set right?.

Might be Translator Plus time (grin)

 

[BM Computer Src]

problem solved. It was a bad ground; ithe wire had come loose of the ring terminator. It was supposed to be secured behind the passenger side head.

Thanks all!